1. Field of the Invention
The present disclosure relates to a non-contact measurement device for a radius of curvature and a thickness of a lens and a measurement method thereof, in particular, to a measurement device and method for detecting the radius of curvature and the thickness of a lens by using a single probe or dual probes.
2. Description of the Related Art
The present invention describes a radius meter for measuring the radius of curvature of a lens and a three dimensional metering instrument for detecting a thickness of the lens used the contact manner. In the case that high surface quality of the lens is required or the lens is too soft, a non-contact manner should be used to prevent the lens from being scraped.
Specifically, the measurement manner for the radius of curvature of spherical lens in the optical industry can be categorized into two kinds, wherein one measures by using an interferometer while another one measures by using a spherical radius meter. The interferometer measures in a non-contact manner, but the establishment cost of the system of the interferometer and the transmission sphere lenses is extremely high, and the measuring range of the radius of curvature is limited since the maximum measurable radius of curvature is limited by the optical scale and the F-number of the transmission sphere lenses. The spherical radius meter calculates the radius of curvature according to the sag or height of the lens, and its measuring range is very wide. However, the spherical radius meter has disadvantages such as, requiring use of a contact probe for measurement, and when high surface quality of the lens is required or the lens is made of soft material, the effective clear aperture of the lens may be scraped or scratched, thus causing the lens necessary rework or possibly rendering the lens unusable.
Regarding the thickness measurement of the lens, the optical industry usually uses the height meter or the three dimensional metering instrument and both of them measure in the contact manner which causes the scraping problem. In the aspect of the non-contact measurement product, most of them are usually suitable for the thickness measurement of the transparent plate, and the current market has a lack of instruments for measuring the center thickness of the lens with a radius of curvature in the non-contact manner. Furthermore, the market instruments cannot have the functions for detecting both of the radius of curvature and the thickness of the lens, and thus while the functions are integrated in one instrument, the cost can be reduced.
Thus, it is clear there is a need for such a measurement device and method for solving the above prior art problems.